1. Field of the Invention
This invention relates to a connector for use in establishing an interconnection to surface pads adjacent the edge of a circuit panel substrate upon insertion of the substrate edgewise into the connector and more particularly relates to a connector employing edge stamped terminals.
2. Description of the Prior Art
Single in-line memory modules represent a high density single in-line package for electronic components such as dynamic random access memory integrated circuit components. A plurality of these components can be mounted in line on a circuit panel whose height is little more than the length of the components themselves. The circuit panels can in turn be mounted on a printed circuit board daughter card which can then be mounted on a printed circuit mother card. The spacing between adjacent daughter boards would then need to be only slightly greater than the height of the individual circuit panels or single in-line memory modules. One approach for mounting single in-line memory modules on a daughter board would be to employ plug in leads adjacent one edge of the circuit panel. These plug in leads can then be connected to conventional printed circuit board contacts such as miniature spring sockets. Miniature spring sockets of this type are shown generally in U.S. Pat. No. 4,072,376. Of course, individual miniature spring sockets would be linearly aligned in order to accept plug in contacts on the edge of the circuit panel. Conventional single in-line edge clips can also be employed.
In addition to modules having plug in leads on the edge of the circuit panel, a plug in circuit panel having surface pads on the surface of the panel substrate extending adjacent the edge of the panel can also be employed. These modules can then be inserted into sockets having contacts aligned to establish a spring biased engagement with the pads on opposite surfaces of the circuit panel substrate. Conventional modules having adjacent pads spaced apart on centerlines of 0.100 inch are commonly employed. A single in-line memory module socket suitable for use with such conventional centerline spacings is disclosed in U.S. Pat. No. 4,557,548; U.S. Pat. No. 4,558,912; and U.S. patent application Ser. No. 800,181 filed Nov. 20, 1985. That connector employs stamped and formed terminals to establish a spring biased contact with the surface pad portions of traces on the module circuit panels.
Another socket used with single in-line memory module circuit panels having surface pads adjacent the edges is disclosed in U.S. Pat. No. 4,575,172. That connector employs a C-shaped spring contact which is stamped and integrally formed from a resilient electrical conductive metallic material, such as a strip of beryllium copper having a thickness of approximately 0.015 inch. To establish contact between the terminal and surface pads on a circuit panel, the surface panel must first be inserted between the ends of the C-shaped member without applying force to the spring terminal and then rotated into position. The contact points engaging opposite sides of the circuit panel are offset, thus requiring a separate latch on the housing to hold the circuit panel in place. Since a large number of contacts are employed on a circuit panel having a relatively high aspect ratio, this configuration stresses the circuit panel itself. Over time, this stress may result in significant warpage and damage to the component to circuit panel interconnection and to the socket to circuit panel interconnection. U.S. Pat. No. 4,577,922 discloses a similar contact in which a dielectric layer is deposited on the terminals themselves in an effort to obtain a closer spacing between adjacent terminals.
The instant invention employs terminals edge stamped from a metal blank so that the terminals can be positioned on centerline spacings significantly less than those obtained using the configuration of U.S. Pat. No. 4,558,912. Furthermore, the socket of the instant invention employs terminals which permit insertion of the circuit panels into the socket with a relatively low insertion force. The fact that the insertion force is not equal to zero is an advantage because the surface pads on the circuit panels are wiped during insertion, thus removing contaminates and corrosion from the surface pads. This wiping action promotes establishment of a sound and reliable electrical interconnection. A terminal which can be employed in this connector is disclosed in a copending application Ser. No. 07/006,538 filed on Jan. 23, 1987 entitled "Low Insertion Force Terminal For Use With Circuit Panel".